Multi-Mode Interference Device Non-Uniform Patch Pattern
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Solution Overview
Problem
Existing optical devices based on multi-mode interference (MMI) face challenges in efficiently manipulating optical signals with multiple wavelengths or polarizations due to their length and complexity, particularly in achieving precise wavelength separation and combination in compact devices.
Innovation Solution
The implementation of a multi-mode interference device with a non-uniform refractive index distribution, achieved through a pattern of irregularly arranged patches, which are optimized using techniques like covariance matrix adaptation evolutionary strategy (CMA-ES) to reduce device length and enhance wavelength selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a uniform pattern of patches is used in the MMI device, then the fabrication process is simpler, but the wavelength separation capability is insufficient for small wavelength separations (20 nm or smaller)
Solution Approach 1:
The patent applies local quality by transitioning from a uniform patch pattern to a non-uniform patch pattern where patch dimensions, spacing, and positions are locally optimized. This allows different regions of the MMI device to have different refractive index modifications tailored to achieve precise wavelength separation for specific wavelength pairs (e.g., 20 nm or smaller separations), thereby improving wavelength separation capability while maintaining fabrication feasibility through systematic design rules.
2Length of moving object
If the MMI device length is reduced for compactness, then the device size is smaller, but the ability to achieve sequential beat length repetitions for wavelength separation is compromised
Solution Approach 1:
The patent applies parameter changes by modifying the refractive index distribution through non-uniform patch patterns. This changes the effective optical path length and phase accumulation characteristics of the MMI device, allowing wavelength separation to be achieved with reduced physical length. The optimized patch configurations enable the device to maintain the necessary beat length repetitions for precise wavelength separation while compacting the overall device footprint.
3Measurement precision
If a non-uniform pattern of patches is implemented to achieve precise wavelength separation, then wavelength manipulation capability is improved, but the device complexity and fabrication difficulty increase
Solution Approach 1:
The patent applies segmentation by dividing the MMI device into multiple discrete patch regions with different refractive index modifications. Each patch can be independently designed and optimized for specific wavelength separation requirements. This segmentation approach allows complex wavelength manipulation functions to be achieved through modular patch configurations, making the design process more systematic and fabrication more manageable through standardized manufacturing techniques.
4Volume of moving object
If the core layer thickness is reduced for device miniaturization, then the device footprint is smaller, but the optical signal confinement and interference effects are weakened
Solution Approach 1:
The patent applies composite materials by combining the core layer with strategically positioned patch structures that have different refractive indices. This composite structure enhances optical signal confinement within the reduced-thickness core through the refractive index contrast provided by the patches. The non-uniform patch pattern creates effective optical boundaries that maintain strong interference effects and wavelength separation capability even when the core layer thickness is reduced for device miniaturization.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for effective manipulation of optical signals with reduced device length and complexity, improving wavelength separation and combination capabilities while minimizing fabrication challenges.
Implementation Method 1
optical devices based on multi-mode interference (MMI) have large bandwidth, are polarization insensitive, and have high fabrication tolerances
Implementation Method 2
The optical signal is concentrated in the core because the core has a high refractive index. The cladding, which has a relatively low refractive index, guides the optical signal along a depth of the device
Data Source
AI summary
A multi-mode interference (MMI) device includes a substrate layer, a core layer grown on the substrate layer for propagating an optical signal, and a cladding layer grown on the core layer for guiding the optical signal. The MMI device also includes a non-uniform pattern of patches forming a non-uniform refractive index distribution within the MMI device.